Process for the separation of substituted alpha- and beta-amino anthraquinones



I Patented Jun e a HUGH ALBERT EDWARD nanscrmn-i wiiimnm sitiirri, Joanjmoms, marginalls nn nssrenonstrro :SCOTCVLISHHDYES, LIMI'rn-n, or QRANGEMQUTH,

rnocnss non THE SEPARATION on SUBSTITUTED ar s amm An'rnRAQUINoNEs- No Drawing. Application ifile d' July 20, 1 9 2 Serial No. 123,732; ianduin Gr eat Britain J'u1ys21',' 192 5.

intention yvith; the separiation of su u e and m no a f q lilw es With specific reference to the prep aration of 2-amii1o 3 chlor anthraquinone, which as prepared applicants claim to be, a; new 7 body.

' N The objectof the invention-is to proyide improved or modifiedprocesses toriprepan ing known .anthraquinone derivatiyes or processes for producing new anthraquinone derivatives. a f;-- i I One of the usual jnethods of obtainingam 'thraquinone derivatives from benzoyl-ben- 'zoic-acid bodiesis-toclose the'ring in the presence of" sulphuric acid. 1 The method when applied to ifghalogenitf-amino) 2;benzoyl abenzoic acids involves the isolation "and drying of the amino-halogen-anthraquinone Heretoforetthe @body obtained by: the condensation of (3',amino-4-chlor) 2-benzoy1- fbenzoic acid to an anthraquinon'e derivative, has'been, stated to "bea single IbodyIWith a melting point of 280 C. to 283 C, 1

J ,We-have carried'out investigations, on'this body, and We have found that -it is composed by making use of their different solubilities insulphuiic acids. of certain concentration.

of at least two bodieswhich can-be separated These two bodies have melting points above ,about300" (1., and below about 200 C, re- 7 spectively. ,Theyfare valuable dyestufi'intermediates; a. w W g 1 i 1 l; a

As a result ofthis, the sulphuric acidmelt after the ring closing, can rber dilute-d to the correct concentration for the separation of theappropriate bodies. I Further, by dilutingthe sulphuric'jacid melt after the ring closing to the, correct concentration the fl-aniino-chlorranthraquinone melting at about 310, C. to 811.5 G. canbe. separated as'its sulphate, and the filtrates further'treated down to about per cent. for the purpose'of obtaining the other apparently isomeric body-melting at about 196 (ltollQFC.

- I'O'ur invention consists in aprocess for the separation of substituted aand ii-amino anthraquinones for the preparation of 2 amino-3 substitute d anthraquinone; which comprises the treatment of the product of flcondensation of (3Tamino-4fgsubstitnted) 2- t or by their equivalents -tration of about aper cent to separate a, product asa sulphate Which,after ;washing 1 q The first-mentioned melting at v about 310311.59;C.,- appears: tobe ing products benz oyl-benzoic bodies by fractional precipitation from sulphuric acid or by fractional crystallization from concentrated by, drochloricfacid or-. fr om organic solvents."

a The i nvention also consists in processes subg stantially as set forth herein, and infprod; ucts such as maybe made i 5T e e e n mpl i in; p by. those Pro es A was hotat;

invention may be. 'c arrieddinto efiect, lre-fer 60 ences to partsbeingto parts ,byweight -Emample J.A ccording :tothis example 3C. aminoi chlor) g2- benz oy1 benzoic acid toclo the r g nd f r m n h on-z nthraquinones.

a a After the sulphuric laci "isicondensed in the presence of sulphuric acid 7 a as .s

iained this is diluted to the correct concentration, namely to asulphuricac d concen: Y

Withwater to hydrolizejthe sulphate and dry-c gingmelts at about 3I0311.5C., being "apparently' ,G-amino-chlor anthraquinonei The filtrates are; then treated by dilution toabout :55 per cent. concentration; as ,a result of which a bodyiwhich is apparently an amino.- rchlor anthraquinone, is, Ipr

ecipi'tated melting: at about 196.1979 3 C V if may, 1 way; that a chlorinated amino-anthraquinone body, 7

amino-3-chlor anthraquinone. On bromina "tion it yields a brominated amino-chlor anthraquinone whi'chcondenses to form chlori},

nated indanthrones and fiavanthrones.

bly 1 Q amino -2 -chlor-4brom-anthraquinone.

This latter ,body'condensestwith organic-bases,

and'has :the constitution.represented by"2+ fonexample; aniline andpara-toluicline,giv-

a 4 b t on su hi mfi on ve ise toifastbluedyestufis. L v 1 E ammple 2.-According to this example, 10 parts of the mixture of amino-chlor-anthraquinmies melting at about 280288 O. obtained by the condensation of (3-amino--lchlor)-2-benzoyl-benzoic acid are dissolved in 60 parts of sulphuric acid of 100 per cent strength.

After solution is complete, 15 parts of wa ter are added, the temperature being below 95 C. It is then finally heated to 120 C. for a short time and cooled to ordinary temperature. It is then allowed to stand for several hours and filtered. The filter cake thus obtained is washed with 80 per cent. sulphuric acid and then with water to free it from sulphuric acid after which it is dried. The product has a light yellowish brown colour and melts at about 310311.5 0., and has the constitution represented by Q-amino- 3-chlor-anthraquinone. The sulphuric acid filtrates are further diluted to 55 per cent. concentration by the addition of water,- then heated to 110 C. to 120 C. for a short time, and cooled to atmospheric temperature. The base crystallizes out. This is filtered off and the cake washed with 55 per cent. sulphuric acid. It is finally washed with water to free it from acid and dried. The product is brick-brown in colour and melts at about 196197 C., and is substantially 1-amino-2- chlor-anthraquinone.

E sample fir-Instead of amino-chlor-benzoyl-benzoic acid other (3-amino-4:-substituted)-2-benzoyl-benzoic acids can be used, and when the two products are separated they can be treated to give bodies which are closely allied to the products mentioned above.

Example 4.-This illustrates the separation into two components of the product obtained on the nitration, reduction and condensation of (4-substituted) -Q-benzoyl-benzoic acids. Processes as described herein may be applied to bodies other than those mentioned therein, for example, the nitration of (4l-substituted) -2-benzoyl-benzoic acid gives products which on reduction and subsequent ring closing give rise to a mixture of substituted amino-anthraquinones. The method of separation described in the case of (3-aniino- 1-chlor) -benzoyl-benzoic acid maybe used for the separation of the a-amino body from the /3-amino body, and this method substantially works also in the case of, for example, a (4-methyl)-2-benzoyl-benzoic acid.

Example 5.-This is a modification of the sulphuric acid process of separation indicated in Examples 1 to 4. According to this example, separation of bodies as indicated above can be effected with solvents other than sulphuric acid, for example by crystallization from concentrated hydrochloric acid a product can be obtained which contains substantially less of the substituted a-amino than is present in the original mixture. 6 parts of the mixture are boiled with 10 parts of concentrated hydrochloric acid, and after cooling to 7 5 C. the mixture is filtered. The ocamino body is more soluble in the hot acid than the B-amino body.

E mample 6.This is a modification of Example 5. According to this example, the bodies are separated by the use of organic solvents.

Dealing more particularly with the mixture of amino-chlor-anthraquinones that is obtained by a ring closing of (3-amino-4- chlor) -2-benzoyl-benzoic acid, we have found that if the crude mixture is dissolved in organic solvents, the product that crystallizes out is generally the 2-amino-3-chlor body, and although with different solvents a varying degree of purification is obtained, yet as a rule the product that crystallizes out from the organic solvents contains appreciably less of the a-aminochlor isomer than the original mixture of amino-bodies, that was dissolved in the solvents, so that repeated crystallizations from organic solvents give the Q-amino- 3-chlor isomer in a fairly pure state.

In this connection we have found that amongst the most suitable solvents may be mentioned aniline, nit-robenzene, tetrachlorethane and solvent naphtha. Phenol, cresol and such like bodies can also be used, as the halogenated amino-chlor anthraquinones are fairly soluble in this type of solvent. Acetic acid, pyridine, acetone and ethyl phthalate can be used, although we do not regard them as quite as efiective as the first mentioned. lVe regard the degree of purification obtained with the ordinary alcohols such as the methyl and butyl alcohol as less satisfactory.

E mam-plea 7.This deals with a preparation and separation of brom derivatives.

When brom-benzene is condensed with phthalic anhydride in the usual way, the product obtained (4 -brom) 2 benzoyl 'benzoic acidcan be nitrated and reduced to the (3-amino-4c-brom) -2benzoyl-benzoic acid. This product on ring closing in the usual way appears to give a mixture of two isomeric bodies which are apparently the 1- amino-2-brom-anthraquinone and the amino-3-brom-anthraquinone. If this mixture of isomers is treated by the methods outlined above for the separation of the corresponding amino-chlor isomers they can be separated into 2-amino-3-brom anthraquinone and 1-amino-2-brom anthraquino-ne.

E wample 8.This deals with a method of separating isomers such as those prepared by the process of Example 7 by means of sulphuric acid. 5 parts of (3-aminol-brom) -2-benzoyl-benzoic acid are dissolved in 30 parts monohydrate sulphuric acid, and the mixture is stirred for 15 minutes at 180 C. After cooling to C. water is Very slowly added to the mixture which is stirred until the concentration of the acid is reduced to 80%.

The mixture is then stirred for a quarter of 1 an hour at 80 (3., cooled to 30 0., filtered, washed with 80% sulphuric acid, and then washed acid free with water.

I garded as 2-amino-3-brom anthraquinone.

The product obtained its alpale yellowish orange body of melting point 293302 C. It contains/substantially no brom a-amino 'anthraquinone, and when dissolved in sulphuric acid, gives a yellow solution. On re-- crystallization from chlor benzene, a product is obtained which melts, at 305306.5 C. The constitution of thebody may be re- On brominating this body by treating it in water suspension with bromine, a reddish yellow product is obtained which melts at about 240 C. This body maybe regarded as 1 3-dibrom-2-amino anthraquinone.

.Ewample 9.-'This deals with the working 7 up of the filtrates of Example 8. The acid filtrates of Example 8 are drowned in water, and the precipitated body filtered H and Washed acid free. It is a bright red colour and, when dissolved in sulphuric acid, gives; a yellow solution. It meltsat 203-215 C., and consists chiefly of 1-ainino-2-brom anthraquinone which contains a very small percentage of ,B-aminO anthraquinone.

Example 10.This deals with a method of 7 separation of the products obtained by the ring closing of (3'-amino-4-n1ethyl)'-2-benzoyl-benzoic acid. A mixture is prepared comprising parts (3-amino-4-methyl) -2- benzoyl-benzoic acid, and 90 parts monohydrate sulphuric acid. I f c The above mixture is heated at 180 C. for 15 minutes, cooled'to 70 C., and suflicient water slowly added with stirring to reduce the concentration ofthe acid to 80%. The

mixture is then stirred for a quarter of an hour at C., cooled to below 30 C. and the sulphate which formed filtered off, washed with 80% sulphuric acid andthen with water until acid free. i

of which are valuable intermediates for the production of dyestuffs.

The invention may quinone derivatives, closely relate-d to those referred to in the above examples, viz., those derived from (3-amino-4-substituted)-2- benzoyl-benzoic acids-,for instance, those derived from (3'-amino-4--halogen) -2-benzoylbenzoic acid, V a,

2-amino-3-chlor anthraquinone prepared as herein described is a substance which melts at about 310311.5 0., the sulphate of which is substantially insoluble in sulphuric acid of a concentration of-about 80%, but soluble in sulphuric acid of higher concentration; v The free amino bod has a light yellowish: brown colour. On romination, it yields a brominated-amino-chlor anthraquinone which condenses to form chlorinated indanthrones n flavanthrones.

VVeclaimt 1 1. As an article of manufacture, '2-amino-3- chlor-anthraquinone in such a state of purity as to have a melting point of about 310 to 311.5' C.

2. A process which comprisesthe'separ'ationof the products of ring-closure of 2- benzoyl-benzoic acid-3-amino-4-chlor .by fractionalprecipitation from sulphuric acid of about 80% strength.

- In testimony whereof we have names to this-specification.

- HUGH ALBERT EDWARD DRESCHER.

WILLIAM SMlTl-Ll i JOHN THOMAS.-

signed our An orange coloured product is obtained a containing substantially no u-amino anthra- General The method of separation according to Example 8 and other examples herein given can also be applied to brominated mixed products, and in this way two different dibrom- I amino-anthraquinones can be obtained, both be applied to anthraice I 

